It has conventionally been carried out to add a beautiful luster of pearls to a container whose appearance is of importance.
One of the generally employed techniques to add a pearly luster comprises applying plate crystals of pearly lusterimparting agents, such as fish scale guanine, talc powder, various lead salts, mica, and titanium pearlescent pigments, on the surface of an object or kneading these pearlescent agents into an object.
A thermoplastic resin composition comprising 5 to 94% by weight of a polyacrylate resin, 0.5 to 70% by weight of a saturated aliphatic polyolefin resin, and 5 to 94% by weight of a polystyrene resin or an aromatic polyester resin is known to have a pearly luster as disclosed in JP-B-46-31467 (the term "JP-B" as used herein means an "examined published Japanese patent application").
Also known is a resin container with a metallic luster comprising 10 to 99% by weight of a polyester resin and 1 to 90% by weight of a polyolefin resin, the thin wall of which has been oriented at least uniaxially, as disclosed in JP-B-61-39336.
Further, JP-B-62-58974 discloses a polyester hollow container having a matte pearly luster comprising a blend of a thermoplastic polyester resin containing ethylene terephthalate as a main repeating unit and having an intrinsic viscosity of from 0.75 to 1.40 and at least one member, selected from the group consisting of a methacrylate resin, a saturated fatty acid polyolefin resin, and a styrene resin, produced by blow molding with biaxial stretch and matte-finishing.
According to the method of applying or kneading a pearly luster-imparting agent, the pearly luster obtained lacks depth because it is given from the agent existing on the surface of an object. Moreover, the pearly luster-imparting agents are expensive, increasing the cost.
Any of the above-described conventional techniques, though able to give a pearly luster to a container itself (e.g., bottles), only provides an opaque container due to a large proportion of the pearly luster-imparting agent or the pearlescent resin so that the content of the container, e.g., cosmetics, cannot be seen from the outside, and one cannot tell the hue or the residue of the content in the opaque container.
In addition, since any of the compositions according to the above-described conventional techniques are compounded with a substantial amount of other resins than a polyester resin, the properties of the polyester resin are changed, resulting in deterioration of moldability when preformed, and non-uniformity of a section when blow molded.